Dental implants are widely used as artificial substitutes for the root portion of missing teeth, and allow a tooth prosthesis to be securely anchored to the jaw via a permanent abutment mounted to the implant. Endosseous implants generally comprise an externally threaded body, often self-taping into the bone tissues, and further comprise an internal chamber that is configured, typically internally threaded, for receiving and securing therein the anchoring stem of a permanent abutment therein.
Following implantation of an implant in the intra oral cavity and healing of the surrounding tissues, a physical model of the intra oral cavity is produced for facilitating design and manufacture of the permanent abutment and prosthesis or other restoration that is to be eventually mounted onto the implant. In one procedure, an impression abutment is mounted to the implant so that it projects into the intra oral cavity, and an impression is then obtained of the intraoral cavity using well known techniques and impression materials, for example PVS. The impression abutment may be of the pick-up type, to be embedded with the impression material and retained therein after the impression tray is removed. Alternatively the impression tray is removed without the impression abutment attached thereto, but nevertheless having a recess formed therein complementary to the outer shape of the impression abutment, enabling the transfer-type impression abutment to be mounted therein at a later time. Subsequently an analog, corresponding to the particular implant that is implanted in the patient, is attached to the abutment, which is in situ in the impression material, and plaster is poured into the impression tray including the analog to produce a positive plaster model of the intraoral cavity with the analog embedded. The analog, in particular the internal passage thereof which is substantially identical to the internal passage of the implant that is designed to receive, engage and secure the permanent abutment, is in a position and orientation in the plaster model corresponding to the position and orientation of the implant in the patient's intra oral cavity. The dental technician can now attach a permanent abutment, or custom design a permanent abutment to fit the implant, build a coping or bridge framework or prosthesis to fit into the intraoral cavity of the patient.
By way of general background, the following publications relate to implants:
U.S. Pat. No. 6,358,052 discloses a dental implant system and method for effecting a dental restoration using the same. The dental implant system having an implant fixture adapted to be deployed in a bone; an impression coping adapted to be selectively deployed on the implant fixture and in a dental impression; a laboratory analog adapted to be selectively deployed on the impression coping and in a dental cast; a spherical abutment adapted to be selectively deployed on the laboratory analog; and a multiaxis abutment adapted to be adjustably deployed on the spherical abutment; wherein the spherical abutment and the multiaxis abutment are used to generate a cast permanent abutment which may be received by the laboratory analog and the implant fixture.
US 2008/032262 discloses a dental implant system comprising an implant member, an abutment member and a transfer key with cooperatively engaging structures for ensuring proper alignment and orientation of an abutment assembled on the implant member and for preparing an accurate dental impression and mold which represents the implantation site and its relationship to adjacent teeth structures. A dental reconstruction method utilizing the dental implant system of the present invention is also disclosed.
US 2006/183078 discloses a one-piece, screw-receiving, externally-threaded endosseous dental implant that includes a body portion with external threading and, at its proximal end, an unthreaded, cylindrical portion including a retentive groove for engaging a complementary transfer component or comfort cap; a one- or two-piece screw-receiving implant abutment for attachment to a one or two-piece implant, including a retentive groove for engaging a complementary transfer component or comfort cap; and a fixture mount for insertion in a one-piece implant, that can be sectioned with the distal end used to extend the implant height.